The residents of the International Space Station turned their attention to spacewalk preparations this week as they gear up for a six-hour excursion outside the complex June 1.

During the spacewalk, the crew will repair and retrieve U.S. and Russian hardware.

Expedition 13 Commander Pavel Vinogradov and NASA Flight Engineer and Science Officer Jeff Williams gathered equipment for the spacewalk, charged batteries for the Russian Orlan suits they will wear and checked out systems in the Pirs Docking Compartment airlock. The spacewalk will be staged from Pirs.

This will be the 65th spacewalk in support of station assembly and maintenance and the 18th conducted from this airlock. This will be the sixth spacewalk in Vinogradov's career and the second for Williams.

The crew members will climb into their spacesuits next Tuesday to test their mobility and to handle tools they will use while conducting their work outside. Vinogradov and Williams shifted their wake and sleep cycles this week to match the hours they will work on June 1. They will enjoy some off-duty time this weekend before resuming spacewalk preparations on Monday, with final communications and systems checks on their suits.

During the spacewalk the crew will install a new hydrogen vent valve on the hull of the Zvezda Service Module to bypass a similar valve that is clogged. The vent valve is part of the Russian Elektron oxygen-generation system that separates oxygen and hydrogen from water in the device's plumbing unit. The oxygen is then circulated into the cabin atmosphere while hydrogen is released overboard.

The spacewalkers will also recover a thruster residue collection device from Zvezda, retrieve a contamination monitoring device and a package of biology experiments and reposition a cable for a navigation antenna on the aft end of Zvezda to be used next year for the unpiloted rendezvous and docking of the new European Automated Transfer Vehicle.

Williams will also replace a camera on the station's Mobile Base System railcar that moves up and down the truss of the complex.

On the maintenance front, Vinogradov this week finished replacing a gas analyzer device for the Russian carbon dioxide removal system, known as Vozdukh. It had been operating at a slightly decreased rate in cleansing carbon dioxide from the cabin atmosphere. Russian specialists reactivated the system following the installation of the new gas analyzer. Vozdukh is now operating normally.

As part of the Crew Earth Observations experiment, Williams snapped the first shots of the Cleveland volcano erupting on the Aleutian Islands in Alaska. From their perspective in orbit, astronauts have been the first to spot and confirm the volcanic eruptions on several occasions. This is the first early sighting of a new eruption in recent years.

On Tuesday, Williams discussed the progress of his mission with the Associated Press Television Network and conducted an amateur radio discussion with students at a school in Venice, Italy.

Williams began runs of an experiment, designated the Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions, or InSPACE. The fluid physics experiment, last operated during Expedition 7, studies the behavior of fluids that change their properties when in a magnetic field. InSPACE obtains basic data on a new class of smart materials that can be used to improve or develop new brake systems, seat suspensions robotics, clutches, airplane landing gear and vibration damper systems.

Williams also continued checking the camera for the ground-commanded Binary Colloidal Alloy Test, or BCAT-3 activity. The EarthKAM camera and equipment is taking time-lapse photography once every hour of BCAT sample 3. BCAT-3 uses small particles called colloids to study fundamental physics. It gathers data that may provide insight into a wide range of applications, from the development of new pharmaceuticals to new rocket engines. NASA's payload operations team at the agency's Marshall Space Flight Center, Huntsville, Ala., coordinates U.S. science activities on the station.